// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/metrics/persistent_histogram_allocator.h"

#include "base/files/file.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/bucket_ranges.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/persistent_memory_allocator.h"
#include "base/metrics/statistics_recorder.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace base {

class PersistentHistogramAllocatorTest : public testing::Test {
 protected:
  const int32_t kAllocatorMemorySize = 64 << 10;  // 64 KiB

  PersistentHistogramAllocatorTest()
      : statistics_recorder_(StatisticsRecorder::CreateTemporaryForTesting()) {
    CreatePersistentHistogramAllocator();
  }
  ~PersistentHistogramAllocatorTest() override {
    DestroyPersistentHistogramAllocator();
  }

  void CreatePersistentHistogramAllocator() {
    allocator_memory_.reset(new char[kAllocatorMemorySize]);

    GlobalHistogramAllocator::ReleaseForTesting();
    memset(allocator_memory_.get(), 0, kAllocatorMemorySize);
    GlobalHistogramAllocator::GetCreateHistogramResultHistogram();
    GlobalHistogramAllocator::CreateWithPersistentMemory(
        allocator_memory_.get(), kAllocatorMemorySize, 0, 0,
        "PersistentHistogramAllocatorTest");
    allocator_ = GlobalHistogramAllocator::Get()->memory_allocator();
  }

  void DestroyPersistentHistogramAllocator() {
    allocator_ = nullptr;
    GlobalHistogramAllocator::ReleaseForTesting();
  }

  std::unique_ptr<StatisticsRecorder> statistics_recorder_;
  std::unique_ptr<char[]> allocator_memory_;
  PersistentMemoryAllocator* allocator_ = nullptr;

 private:
  DISALLOW_COPY_AND_ASSIGN(PersistentHistogramAllocatorTest);
};

TEST_F(PersistentHistogramAllocatorTest, CreateAndIterate) {
  PersistentMemoryAllocator::MemoryInfo meminfo0;
  allocator_->GetMemoryInfo(&meminfo0);

  // Try basic construction
  HistogramBase* histogram = Histogram::FactoryGet(
      "TestHistogram", 1, 1000, 10, HistogramBase::kIsPersistent);
  EXPECT_TRUE(histogram);
  histogram->CheckName("TestHistogram");
  PersistentMemoryAllocator::MemoryInfo meminfo1;
  allocator_->GetMemoryInfo(&meminfo1);
  EXPECT_GT(meminfo0.free, meminfo1.free);

  HistogramBase* linear_histogram = LinearHistogram::FactoryGet(
      "TestLinearHistogram", 1, 1000, 10, HistogramBase::kIsPersistent);
  EXPECT_TRUE(linear_histogram);
  linear_histogram->CheckName("TestLinearHistogram");
  PersistentMemoryAllocator::MemoryInfo meminfo2;
  allocator_->GetMemoryInfo(&meminfo2);
  EXPECT_GT(meminfo1.free, meminfo2.free);

  HistogramBase* boolean_histogram = BooleanHistogram::FactoryGet(
      "TestBooleanHistogram", HistogramBase::kIsPersistent);
  EXPECT_TRUE(boolean_histogram);
  boolean_histogram->CheckName("TestBooleanHistogram");
  PersistentMemoryAllocator::MemoryInfo meminfo3;
  allocator_->GetMemoryInfo(&meminfo3);
  EXPECT_GT(meminfo2.free, meminfo3.free);

  std::vector<int> custom_ranges;
  custom_ranges.push_back(1);
  custom_ranges.push_back(5);
  HistogramBase* custom_histogram = CustomHistogram::FactoryGet(
      "TestCustomHistogram", custom_ranges, HistogramBase::kIsPersistent);
  EXPECT_TRUE(custom_histogram);
  custom_histogram->CheckName("TestCustomHistogram");
  PersistentMemoryAllocator::MemoryInfo meminfo4;
  allocator_->GetMemoryInfo(&meminfo4);
  EXPECT_GT(meminfo3.free, meminfo4.free);

  PersistentMemoryAllocator::Iterator iter(allocator_);
  uint32_t type;
  EXPECT_NE(0U, iter.GetNext(&type));  // Histogram
  EXPECT_NE(0U, iter.GetNext(&type));  // LinearHistogram
  EXPECT_NE(0U, iter.GetNext(&type));  // BooleanHistogram
  EXPECT_NE(0U, iter.GetNext(&type));  // CustomHistogram
  EXPECT_EQ(0U, iter.GetNext(&type));

  // Create a second allocator and have it access the memory of the first.
  std::unique_ptr<HistogramBase> recovered;
  PersistentHistogramAllocator recovery(
      std::make_unique<PersistentMemoryAllocator>(
          allocator_memory_.get(), kAllocatorMemorySize, 0, 0, "", false));
  PersistentHistogramAllocator::Iterator histogram_iter(&recovery);

  recovered = histogram_iter.GetNext();
  ASSERT_TRUE(recovered);
  recovered->CheckName("TestHistogram");

  recovered = histogram_iter.GetNext();
  ASSERT_TRUE(recovered);
  recovered->CheckName("TestLinearHistogram");

  recovered = histogram_iter.GetNext();
  ASSERT_TRUE(recovered);
  recovered->CheckName("TestBooleanHistogram");

  recovered = histogram_iter.GetNext();
  ASSERT_TRUE(recovered);
  recovered->CheckName("TestCustomHistogram");

  recovered = histogram_iter.GetNext();
  EXPECT_FALSE(recovered);
}

TEST_F(PersistentHistogramAllocatorTest, CreateWithFile) {
  const char temp_name[] = "CreateWithFileTest";
  ScopedTempDir temp_dir;
  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
  FilePath temp_file = temp_dir.GetPath().AppendASCII(temp_name);
  const size_t temp_size = 64 << 10;  // 64 KiB

  // Test creation of a new file.
  GlobalHistogramAllocator::ReleaseForTesting();
  GlobalHistogramAllocator::CreateWithFile(temp_file, temp_size, 0, temp_name);
  EXPECT_EQ(std::string(temp_name),
            GlobalHistogramAllocator::Get()->memory_allocator()->Name());

  // Test re-open of a possibly-existing file.
  GlobalHistogramAllocator::ReleaseForTesting();
  GlobalHistogramAllocator::CreateWithFile(temp_file, temp_size, 0, "");
  EXPECT_EQ(std::string(temp_name),
            GlobalHistogramAllocator::Get()->memory_allocator()->Name());

  // Test re-open of an known-existing file.
  GlobalHistogramAllocator::ReleaseForTesting();
  GlobalHistogramAllocator::CreateWithFile(temp_file, 0, 0, "");
  EXPECT_EQ(std::string(temp_name),
            GlobalHistogramAllocator::Get()->memory_allocator()->Name());

  // Final release so file and temp-dir can be removed.
  GlobalHistogramAllocator::ReleaseForTesting();
}

TEST_F(PersistentHistogramAllocatorTest, CreateSpareFile) {
  const char temp_name[] = "CreateSpareFileTest.pma";
  ScopedTempDir temp_dir;
  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
  FilePath temp_file = temp_dir.GetPath().AppendASCII(temp_name);
  const size_t temp_size = 64 << 10;  // 64 KiB

  ASSERT_TRUE(GlobalHistogramAllocator::CreateSpareFile(temp_file, temp_size));

  File file(temp_file, File::FLAG_OPEN | File::FLAG_READ);
  ASSERT_TRUE(file.IsValid());
  EXPECT_EQ(static_cast<int64_t>(temp_size), file.GetLength());

  char buffer[256];
  for (size_t pos = 0; pos < temp_size; pos += sizeof(buffer)) {
    ASSERT_EQ(static_cast<int>(sizeof(buffer)),
              file.ReadAtCurrentPos(buffer, sizeof(buffer)));
    for (size_t i = 0; i < sizeof(buffer); ++i)
      EXPECT_EQ(0, buffer[i]);
  }
}

TEST_F(PersistentHistogramAllocatorTest, StatisticsRecorderMerge) {
  const char LinearHistogramName[] = "SRTLinearHistogram";
  const char SparseHistogramName[] = "SRTSparseHistogram";
  const size_t starting_sr_count = StatisticsRecorder::GetHistogramCount();

  // Create a local StatisticsRecorder in which the newly created histogram
  // will be recorded. The global allocator must be replaced after because the
  // act of releasing will cause the active SR to forget about all histograms
  // in the relased memory.
  std::unique_ptr<StatisticsRecorder> local_sr =
      StatisticsRecorder::CreateTemporaryForTesting();
  EXPECT_EQ(0U, StatisticsRecorder::GetHistogramCount());
  std::unique_ptr<GlobalHistogramAllocator> old_allocator =
      GlobalHistogramAllocator::ReleaseForTesting();
  GlobalHistogramAllocator::CreateWithLocalMemory(kAllocatorMemorySize, 0, "");
  ASSERT_TRUE(GlobalHistogramAllocator::Get());

  // Create a linear histogram for merge testing.
  HistogramBase* histogram1 =
      LinearHistogram::FactoryGet(LinearHistogramName, 1, 10, 10, 0);
  ASSERT_TRUE(histogram1);
  EXPECT_EQ(1U, StatisticsRecorder::GetHistogramCount());
  histogram1->Add(3);
  histogram1->Add(1);
  histogram1->Add(4);
  histogram1->AddCount(1, 4);
  histogram1->Add(6);

  // Create a sparse histogram for merge testing.
  HistogramBase* histogram2 =
      SparseHistogram::FactoryGet(SparseHistogramName, 0);
  ASSERT_TRUE(histogram2);
  EXPECT_EQ(2U, StatisticsRecorder::GetHistogramCount());
  histogram2->Add(3);
  histogram2->Add(1);
  histogram2->Add(4);
  histogram2->AddCount(1, 4);
  histogram2->Add(6);

  // Destroy the local SR and ensure that we're back to the initial state and
  // restore the global allocator. Histograms created in the local SR will
  // become unmanaged.
  std::unique_ptr<GlobalHistogramAllocator> new_allocator =
      GlobalHistogramAllocator::ReleaseForTesting();
  local_sr.reset();
  EXPECT_EQ(starting_sr_count, StatisticsRecorder::GetHistogramCount());
  GlobalHistogramAllocator::Set(std::move(old_allocator));

  // Create a "recovery" allocator using the same memory as the local one.
  PersistentHistogramAllocator recovery1(
      std::make_unique<PersistentMemoryAllocator>(
          const_cast<void*>(new_allocator->memory_allocator()->data()),
          new_allocator->memory_allocator()->size(), 0, 0, "", false));
  PersistentHistogramAllocator::Iterator histogram_iter1(&recovery1);

  // Get the histograms that were created locally (and forgotten) and merge
  // them into the global SR. New objects will be created.
  std::unique_ptr<HistogramBase> recovered;
  while (true) {
    recovered = histogram_iter1.GetNext();
    if (!recovered)
      break;

    recovery1.MergeHistogramDeltaToStatisticsRecorder(recovered.get());
    HistogramBase* found =
        StatisticsRecorder::FindHistogram(recovered->histogram_name());
    EXPECT_NE(recovered.get(), found);
  };
  EXPECT_EQ(starting_sr_count + 2, StatisticsRecorder::GetHistogramCount());

  // Check the merged histograms for accuracy.
  HistogramBase* found = StatisticsRecorder::FindHistogram(LinearHistogramName);
  ASSERT_TRUE(found);
  std::unique_ptr<HistogramSamples> snapshot = found->SnapshotSamples();
  EXPECT_EQ(found->SnapshotSamples()->TotalCount(), snapshot->TotalCount());
  EXPECT_EQ(1, snapshot->GetCount(3));
  EXPECT_EQ(5, snapshot->GetCount(1));
  EXPECT_EQ(1, snapshot->GetCount(4));
  EXPECT_EQ(1, snapshot->GetCount(6));

  found = StatisticsRecorder::FindHistogram(SparseHistogramName);
  ASSERT_TRUE(found);
  snapshot = found->SnapshotSamples();
  EXPECT_EQ(found->SnapshotSamples()->TotalCount(), snapshot->TotalCount());
  EXPECT_EQ(1, snapshot->GetCount(3));
  EXPECT_EQ(5, snapshot->GetCount(1));
  EXPECT_EQ(1, snapshot->GetCount(4));
  EXPECT_EQ(1, snapshot->GetCount(6));

  // Perform additional histogram increments.
  histogram1->AddCount(1, 3);
  histogram1->Add(6);
  histogram2->AddCount(1, 3);
  histogram2->Add(7);

  // Do another merge.
  PersistentHistogramAllocator recovery2(
      std::make_unique<PersistentMemoryAllocator>(
          const_cast<void*>(new_allocator->memory_allocator()->data()),
          new_allocator->memory_allocator()->size(), 0, 0, "", false));
  PersistentHistogramAllocator::Iterator histogram_iter2(&recovery2);
  while (true) {
    recovered = histogram_iter2.GetNext();
    if (!recovered)
      break;
    recovery2.MergeHistogramDeltaToStatisticsRecorder(recovered.get());
  };
  EXPECT_EQ(starting_sr_count + 2, StatisticsRecorder::GetHistogramCount());

  // And verify.
  found = StatisticsRecorder::FindHistogram(LinearHistogramName);
  snapshot = found->SnapshotSamples();
  EXPECT_EQ(found->SnapshotSamples()->TotalCount(), snapshot->TotalCount());
  EXPECT_EQ(1, snapshot->GetCount(3));
  EXPECT_EQ(8, snapshot->GetCount(1));
  EXPECT_EQ(1, snapshot->GetCount(4));
  EXPECT_EQ(2, snapshot->GetCount(6));

  found = StatisticsRecorder::FindHistogram(SparseHistogramName);
  snapshot = found->SnapshotSamples();
  EXPECT_EQ(found->SnapshotSamples()->TotalCount(), snapshot->TotalCount());
  EXPECT_EQ(1, snapshot->GetCount(3));
  EXPECT_EQ(8, snapshot->GetCount(1));
  EXPECT_EQ(1, snapshot->GetCount(4));
  EXPECT_EQ(1, snapshot->GetCount(6));
  EXPECT_EQ(1, snapshot->GetCount(7));
}

TEST_F(PersistentHistogramAllocatorTest, RangesDeDuplication) {
  // This corresponds to the "ranges_ref" field of the PersistentHistogramData
  // structure defined (privately) inside persistent_histogram_allocator.cc.
  const int kRangesRefIndex = 5;

  // Create two histograms with the same ranges.
  HistogramBase* histogram1 =
      Histogram::FactoryGet("TestHistogram1", 1, 1000, 10, 0);
  HistogramBase* histogram2 =
      Histogram::FactoryGet("TestHistogram2", 1, 1000, 10, 0);
  const uint32_t ranges_ref = static_cast<Histogram*>(histogram1)
                                  ->bucket_ranges()
                                  ->persistent_reference();
  ASSERT_NE(0U, ranges_ref);
  EXPECT_EQ(ranges_ref, static_cast<Histogram*>(histogram2)
                            ->bucket_ranges()
                            ->persistent_reference());

  // Make sure that the persistent data record is also correct. Two histograms
  // will be fetched; other allocations are not "iterable".
  PersistentMemoryAllocator::Iterator iter(allocator_);
  uint32_t type;
  uint32_t ref1 = iter.GetNext(&type);
  uint32_t ref2 = iter.GetNext(&type);
  EXPECT_EQ(0U, iter.GetNext(&type));
  EXPECT_NE(0U, ref1);
  EXPECT_NE(0U, ref2);
  EXPECT_NE(ref1, ref2);

  uint32_t* data1 =
      allocator_->GetAsArray<uint32_t>(ref1, 0, kRangesRefIndex + 1);
  uint32_t* data2 =
      allocator_->GetAsArray<uint32_t>(ref2, 0, kRangesRefIndex + 1);
  EXPECT_EQ(ranges_ref, data1[kRangesRefIndex]);
  EXPECT_EQ(ranges_ref, data2[kRangesRefIndex]);
}

}  // namespace base